Finally, I estimated the probability that a new nominated-based game would fail to take off. When transmission is modelled as a standard branching process with Poisson offspring distribution and mean \(R_0\) , the probability that an outbreak starting with one initial case goes extinct is \(1-1/R_0\)  [1]}. Hence an \(R_0\) =1.9–2.5 would suggest that only 48–60% of index cases in nomination-based games successfully go on to generate a large outbreak. If transmission involves superspreading events (i.e. there is individual-level variation in \(R_0\) ) this proportion would be even smaller [1]}.
